Can animals really think? Can they make decisions based on information? For years, scientists have debated these questions. Now, many of them believe that some animals have the brain power to understand new situations, make decisions, and plan ahead. The following are just a few of the many examples of animal intelligence that scientists have observed.
A hungry chimpanzee walking through his native rain forest comes upon a large Panda oleosa nut lying on the ground under one of the widely scattered Panda trees. He knows that these nuts are much too hard to open with his hands or teeth and that although he can use pieces of wood or relatively soft rocks to batter open the more abundant Coula edulis nuts, these tough Panda nuts can only be cracked by pounding them with a very hard piece of rock. Very few stones are available in the rain forest, but he walks 80 meters straight to another tree where several days ago he had cracked open a Panda nut with a large chunk of granite. He carries this rock back to the nut he has just found, places it in a crotch between two buttress roots, and cracks it open with a few well-aimed blows.
In a city park in Japan, a hungry green-backed heron picks up a twig, breaks it into small pieces, and carries one of these to the edge of a pond, where she drops it into the water. At first it drifts away, but she picks it up and brings it back. She watches the floating twig intently until small minnows swim up to it, and she then seizes one by a rapid thrusting grab with her long, sharp bill. Another green-backed heron from the same colony carries bits of material to a branch extending out over the pond and tosses the bait into the water below. When minnows approach this bait, he flies down and seizes one on the wing.
Many animals adapt their behavior to the challenges they face either under natural conditions or in laboratory experiments. For example, in other parts of Africa chimpanzees select suitable branches from which they break off twigs to produce a slender probe, which they carry some distance to poke it into a termite nest and eat the termites clinging to it as it is withdrawn. Apes have also learned to use artificial communication systems to ask for objects and activities they want and to answer simple questions about pictures of familiar things. Vervet monkeys employ different alarm calls to inform their companions about particular types of predator.
Such ingenuity is not limited to primates. Lionesses sometimes cooperate in surrounding prey or drive prey toward a companion waiting in a concealed position. They are also very ingenious at plugging water leaks, sometimes cutting pieces of wood to fit a particular hole through which water is escaping. Under natural conditions, in late winter some beavers cut holes in the dams they have previously constructed, causing the water level to drop, which allows them to swim about under the ice without holding their breath.
Nor is appropriate adaptation of complex behavior to changing circumstances a mammalian monopoly. Bowerbirds construct and decorate bowers that help them attract females for mating. Plovers carry out injury-simulating distraction displays that lead predators away from their eggs or young, and they adjust these displays according to the intruder's behavior.
At the University of Arizona, a gray parrot named Alex surprised his trainer, Irene Pepperberg. She has been working with Alex for 15 years, teaching him to talk, name and count objects, and answer simple questions about them. He is very good at these tasks. He even says, "I'm sorry" when he makes a mistake answering a question. But what Alex once did outside of the laboratory was even more impressive. When he had to go to the veterinarian's office for lung surgery, he became upset. As Pepperberg started to leave, Alex said, "Come here. I love you. I'm sorry. I want to go back." Alex thought he was being punished for doing something wrong. He seemed able to use language to express his thoughts.
Certain insects, specifically the honeybees, employ symbolic gestures to communicate the direction and distance their sisters must fly to reach food or other things that are important to the colony.
These are only a few of the more striking examples of versatile behavior on the animals Although these are not routine everyday occurrences, the fact that animals are capable of such versatility has led to a subtle shift on the part of some scientists concerned with animal behavior. Rather than insisting that animals do not think at all, many scientists now believe that they sometimes experience at least simple thoughts, although these thoughts are probably different from any of ours. |
